Liu Houcang, Xie Lixin, Hu Longji
Institute of Ophthalmology & Eye Hospital, Shandong Academy of Medical Sciences, Qingdao 266071, China.
Zhonghua Yan Ke Za Zhi. 2002 Jan;38(1):24-7.
To study the histologic changes in rabbit corneas after photo-therapeutic keratectomy (PTK), define the indications and treatment parameters and evaluate efficacy of PTK.
(1) The model of superficial corneal scar in rabbit was made by burn with 8.17% sulfuric acid, and then treated with PTK in two weeks. The corneas were examined with confocal microscope in vivo, nerve staining, light and transmission electron microscope during period after PTK to study the histopathologic changes. (2) Thirty eyes with superficial corneal diseases including 12 eyes with corneal dystrophy, 2 eyes with band degeneration, 10 eyes with scar after infection and trauma and 6 eyes with Dimmer nummular keratitis were treated with PTK. The method of treatment was varied with different diseases. Follow-up was more than six months. To investigate the change of haze, visual acuity, refraction and keratometric power during period after PTK, chi-square tests were used.
(1) Experimental group: in the ablative zone at early time after PTK, there were infiltration of polymorphonuclear leukocytes accompanied by macrophages, proliferation of fibroblast and loose nascent collagen in disorder in the anterior stroma. The wound healing process was stable at six months after PTK. (2) Clinical group: compared with the preoperative visual acuity, the best corrected visual acuity was improved in 21 eyes (70.0%), unchanged in 5 eyes (16.7%) and decreased in 4 eyes (13.3%) at six months after PTK, and the results were better for corneal dystrophy and band degeneration. Haze grade 0.5 was in five eyes, grade I in two eyes and grade 0 the rest. The mean hyperopic shift was + 1.52 D.
The wound healing process in rabbit cornea stabilizes at six months after PTK. PTK is a simple, safe, effective treatment for superficial corneal diseases. The indications for PTK are corneal pathology in the anterior one-third of the cornea, especially corneal dystrophy and band degeneration.
研究准分子激光角膜切削术（PTK）后兔角膜的组织学变化，明确其适应证和治疗参数，并评估PTK的疗效。
（1）用8.17%硫酸烧灼制作兔角膜浅层瘢痕模型，2周后行PTK治疗。PTK术后不同时间段分别用共聚焦显微镜活体观察、神经染色、光镜及透射电镜检查角膜，研究其组织病理学变化。（2）对30只患有浅层角膜疾病的眼睛进行PTK治疗，其中角膜营养不良12只眼、带状变性2只眼、感染及外伤后瘢痕10只眼、点状角膜病变6只眼。根据不同疾病采用不同治疗方法。随访6个月以上。采用卡方检验观察PTK术后不同时间段角膜 haze、视力、屈光及角膜曲率的变化。
（1）实验组：PTK术后早期切削区前基质层有多形核白细胞浸润，伴有巨噬细胞，成纤维细胞增生，新生胶原疏松排列紊乱。PTK术后6个月伤口愈合过程稳定。（2）临床组：PTK术后6个月，与术前视力相比，最佳矫正视力提高21只眼（70.0%），不变5只眼（16.7%），下降4只眼（13.3%），角膜营养不良和带状变性效果较好。haze 0.5级5只眼，Ⅰ级2只眼，其余为0级。平均远视漂移为+1.52D。
PTK术后6个月兔角膜伤口愈合过程稳定。PTK是治疗浅层角膜疾病的一种简单、安全、有效的方法。PTK的适应证为角膜前1/3的病变，尤其是角膜营养不良和带状变性。
